At least they don't play brother and sister, unlike some co-star couples. More co-star hook-ups in our gallery:

"It was such a huge part of my life and no one knew about it," Kaley told Watch magazine about her and Johnny. "It was a wonderful relationship but we never spoke a word about it and never went anywhere together.

"We were so protective of ourselves and the show and didn't want anything to ruin that," she continued. "But that also made it sad, too. That's not the kind of relationship I want — I don't want to be hiding."

Kaley added that her and Johnny's apparently-pretty-recent break-up was "mutual" and that they've continued to work together as usual. Given they play an onscreen couple, "work" sounds pretty awkward...